Device and method for preparing nitric phosphate fertilizer from nitric acid acidolysis phosphorite freezing decalcification mother liquor

Abstract

The invention relates to the technical field of nitric phosphate fertilizer polymerization rate increase and in particular to a device and a method for preparing a nitric phosphate fertilizer from nitric acid acidolysis phosphorite freezing decalcification mother liquor. Mother liquid discharged from a decalcification mother liquor tank is divided into two paths of decalcification mother liquor, aphosphoric acid extraction unit is coupled with a decalcification mother liquor concentration unit, and then the two paths of the decalcification mother liquor can be respectively treated differentlyand are subjected to synthesis treatment in a synthesis pelletizing tower, so that the polymerization rate of the nitric phosphate fertilizer prepared by using a freezing method is increased, and thequality of the nitric phosphate fertilizer is improved.

Description

technical field [0001] The invention relates to the technical field of improving the polymerization rate of nitrophosphate fertilizers, in particular to a device and a method for preparing nitrophosphate fertilizers from nitric acid acid hydrolyzed phosphate rock freezing decalcification mother liquor. Background technique [0002] The production process of freezing nitrophosphate fertilizer is to use nitric acid to acidify the phosphate rock to obtain an acid solution, and then freeze and decalcify the acid solution to obtain a decalcified mother liquor as a raw material to prepare nitrophosphate fertilizer. In the prior art, the decalcified mother liquor is used as a raw material to prepare nitrophosphate fertilizer, which is obtained by neutralizing, concentrating and granulating the decalcified mother liquor. However, in the acidolysis solution system obtained by the freezing method, the main component of the acidolysis solution is Ca(NO 3 ) 2 、H 3 PO 4 、HNO 3 、H 2...

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Problems solved by technology

However, in the acidolysis solution system obtained by the freezing method, the main component of the acidolysis solution is Ca(NO 3 ) 2 、H 3 PO 4 、HNO 3 、H 2 O, the water content is relatively high, but the proportion of phosphate radicals is extremely low. The main reason is that the global phosphate rock grade is generally low, with an average grade of 21.5% (P 2 o 5 ), while in China, medium and low-grade phosphate rocks account for more than 70%, so that when using nitric acid to acidify phosphate rocks and prepare nitrophosphate fertilizers by freezing methods, the quality of phosphate rocks is low, and the polymerization rate of obtained nitrophosphate fertilizers is generally low, which is maintained at 3 for a long time. % below, resulting in lower quality of nitrophosphate fertilizer

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